BRPI1001626A2 - pneumatic tire with a wrap reinforcement - Google Patents

Abstract

TIRE TIRE WITH A WRAPPING STRENGTH. A pneumatic tire includes a radial tarpaulin casing, a tread portion disposed radially out of the carcass, and a crown reinforcement structure interposed between the tread portion and the carcass in circumferential relationship to the carcass. The crown reinforcement structure includes a belt assembly having at least one belt web with reinforcing cords extending parallel to each other and a wrap structure including a nylon reinforced layer extending transversely over the belt assembly and making a angle between -5 degrees and +5 degrees with an equatorial plane of the tire. The nylon reinforcement layer includes nylon strands having a construction of 2000-2200 / 1 Dtex, 1-10 TPI with an end density of 10-35 EPI.

Description

"TIRE TIRE WITH A WRAPPING STRENGTH"

Field of the Invention

The present invention relates generally to pneumatic tires and more specifically to radial casing tires having a textile wrap structure located radially outside the belt assembly.

Background of the Invention

Conventional radial casing tires have a reinforcing member disposed radially out of the belt assembly. The reinforcing member may comprise textile cords oriented at small angles to the circumferential - middle dopneu plane. Such a reinforcing member has been found to be acceptably durable when subjected to high rotational speeds.

Such a reinforcing member, referred to as a wrapper web, may be interposed between the radially outermost web of the belt assembly and the tread and comprises one or more wrappers having a width that is about equal to that of the widest webbing of the webbing. . Alternatively, the wrap canvas may consist of two spaced apart axially spaced canvas portions either radially outwardly of the belt assembly to cover the edges of the radially outermost belt canvas or interposed between the belt canvases so to extend between its edges.

Another alternative for a wrap canvas is the interposition of a helically wound single strand or wire which has been coated with elastomeric material between the radially outermost canvas of the belt assembly and the tread. When winding a single strand is time consuming, conventionally a wrapper sheet is assembled from a 5mm to 30mm wide helically wound strip made of radially outwardly reinforced drawstring for the webs. The conventional wrap reinforcement material is nylon, which has a Young modulus of about 6000 MPa. Such a low modulus allows belt expansion during the tire forming and vulcanizing steps.

It may be desirable to more cheaply provide a pneumatic tire with a wrapping structure having excellent high speed properties, good rolling comfort and resistance, reduced flatspotting, and low noise propagation.

Summary of the Invention

A pneumatic tire according to the present invention includes a radial-bottom housing, a tread portion disposed radially out of the housing, a crown reinforcement structure interposed between the tread portion and the housing in circumferential relationship to the housing. carcass. The crown reinforcement structure includes a stiffening assembly having at least one belt web with reinforcing cords extending parallel to one another and a wrap structure including a nylon reinforced layer extending transversely over the belt assembly and making a In-tre angle -5 degrees and 5 degrees with an equatorial plane of the tire. The nylon reinforced layer includes nylon strands having a TPI 1-10 (S or Z), 2000-2200 / 1 Dtex construction with an end density of 10-35 EPI.

According to another aspect of the present invention, the wrapper structure has two layers with a second layer located adjacent to, and radially outside, a first layer.

In yet another aspect of the present invention, the wrapping layer includes a strip having a width in the range of between 5 mm and 30 mm.

Definitions

The following definitions are controlling for the invention shown.

"Padding" means an elastomeric padding located radially above the bead core and between the pads and the folding canvas.

"Undo" means a ring-like shape.

Tire "Aspect Ratio" means the ratio of its section height (SH) to its section width (SW) multiplied by 100% for expression as a percentage.

"Axial" and "axially" are used herein to refer to lines or directions which are parallel to the tire's axis of rotation.

"Bead" means that part of the tire comprising an annular traction member surrounded by canvas strands and shaped, with or without other reinforcing elements such as bead covers, pads, rubber nail guards and antifrictions, to suit the Hoop drawing.

"Belt structure" means at least two annular layers or parallel-woven tarpaulins, woven or non-woven, underlying the tread, not anchored to each other, and having sloped cords with respect to the equatorial plane of the tire. The running structure may also include parallel cord tarpaulin sloping at relatively low angles acting as restraint layers.

"Shock absorbers" means at least two annular layers or parallel reinforcing cords having the same angle with reference to the equatorial plane of the tire as parallel reinforcing cords on carcasses. Shock absorbers are usually associated with oblique tires.

"Cable" means a cord formed by twisting together two or more bent strands.

"Carcass" means the tire structure apart from belt structure, tread, sub-tread, and side rubber over the pads, but including the heels.

"Anti-friction" refers to narrow strips of material placed around the outer side of the bead to protect canvas from rim laces, distribute bend over rim, and parallel the tire.

"Bead area wire reinforcements" means a reinforcement structure located on the bead portion of the tire.

"Circumferential" means lines or directions extending along the perimeter of the tire surface parallel to the Equatorial Plane (EP) and perpendicular to the axial direction.

"Cord" means one of the reinforcing straps from which the tire pads are comprised.

"Cord angle" means the acute right or left angle in a flat view of the tire formed by a cord with respect to the equatorial plane. The "bank angle" is measured on a cured but not inflated tire.

"Denier" means the weight in grams per 9000 meters (unit for linear density expression). Dtex means the weight in grams per 10,000 meters.

"Elastomer" means a resilient material capable of recovering size and shape after deformation.

"Equatorial plane (EP)" means the plane perpendicular to the axis of rotation of the tire and passing through the center of its tread.

"Tissue" means an essentially unidirectionally extending web of strands, which may be twisted, and which in turn are composed of a plurality of a plurality of (which may also be twisted) filaments of an altomodule material.

"Fiber" is a unit of matter, both natural and man-made, that forms the basic element of filaments, characterized by its length at least 100 times its diameter or width.

"Filament count" means the number of filaments that constitute a thread. Example: 1000 denier polyester has approximately 190 filaments.

"Copper bead" means a reinforced fabric wrapped around bead core.

"Raw Rayon" means unfinished cord or fabric.

"Inner" means towards the inside of the tire and "outer" means towards its outside.

"Inner liner" means the layer or layers of elastomer or other material forming the inner surface of a tubeless tire and containing the inflard fluid of the tire.

"LASE" is the specified elongation load.

"Lateral" means an axial direction.

"Fused strand" means a strand constructed by twisting a plurality of individual strands, at least one of the individual strands being of a material different from the material of at least one of the other individual strands.

"Canvas" means a continuous layer of rubberized parallel cords in the context of a tire and also means a twisted yarn in a yarn context or a cord as used herein meaning is context dependent.

"Polyester" means any polymer synthesized from the polycondensation of a diol and a dicarboxylic acid.

"Radial" and "radially" are used to mean directions radially in or away from the tire's axis of rotation.

"Canvas tire - radial" means a circumferentially or strapped restricted pneumatic tire on which canvas beads extending from bead to bead are placed at bead angles between 65 degrees and 90 degrees with respect to the pneumatic equatorial plane.

"Section Height (SH)" means the radial distance from the nominal dopneumatic rim diameter in its equatorial plane.

"Side" means that portion of a tire between the tread and the tire.

"Tenacity" is the stress expressed as the force per unit of linear density does not deformed specimen (g / tex or g / denier). Used in textiles.

"Tensile" is stress expressed in forces / cross-sectional area. Resistance empsi = 12 800 times specific weight times toughness in grams per denier.

"Tread" means a molded rubber component which, when attached to a tire casing, includes that portion of the tire that contacts the road when the tire is normally inflated and under normal load.

"Twisted" means the number of turns about its axis per unit length of a wire, turns per inch being TPI.

"Yarn" occurs in the following forms: 1) a number of fibers twisted together; 2) a number of filaments placed together in twist; 3) a number of filaments joined together with a degree of twist; 4) a single filament with or without twisting (monofilament);

5) a narrow strip of material with or without twisting.

Brief Description of the Drawings

To make known those skilled in the art most closely related to the present invention, certain exemplary embodiments thereof are now described with reference to the accompanying drawings. These exemplary embodiments are illustrative and may be modified in numerous ways within the spirit and scope of the invention as defined in the claims below.

Fig. 1 is a cross-sectional view of a pneumatic tire for use with the present invention.

Detailed Description of an Example of the Present Invention

Referring to Fig. 1, there is shown an example of a radial-shell pneumatic tire 10 having a pair of substantially non-extensible bead cores 11,13 which are axially spaced with a radial carcass ply 12 extending between the bead cores. The carcass ply 12 is bent axially and radially outwardly from each of the bead cores 11, 13 and is reinforced by cords that are substantially parallel to each other and are at an angle to the equatorial plane (EP) of the tire. -matic example 10.

As used herein, the "equatorial plane" of the example tire 10 is a plane that is perpendicular to the tire's axis of rotation and passes through the center of the tire wheel band 19. The terms "axially" and "axially" refer to if directions that are parallel to the axis of rotation of the example tire 10 and the terms "radially" and "radially" refer to directions that are radially toward or away from the tire's axis of rotation.

The strands of the carcass ply 12 may be made of any suitable material, for example raion, polyester, polyamide, or aromatic polyamide. The crown area 14 of the tire 10 is reinforced by a belt assembly 15 located radially to the tire tread 19. The belt assembly 15 may comprise two concentric belt pads 16, 17, each of which consists of an elastomeric layer reinforced by steel cords or other suitable materials, for example, aromatic polyamide, fiberglass, PVA, carbon fiber, or rayon cords.

Within each belt web 16, 17, the cords may be substantially parallel to each other. The radially innermost belt web cords 16 form an angle of 15 degrees to 30 degrees with the equatorial plane (EP) of the tire 10. While the radially outer belt web cords 17 extend diagonally in the direction opposite to the innermost radial belt canvas cords 16 and form an angle of from -15 degrees to -30 degrees with the equatorial plane (EP) of the tire 10.

In a strand, each of the strands has their component filaments twisted together by a given number of turns per unit length of the yarn (usually expressed in IPT) and additionally the strands are twisted together by a given number of turns per unit of string length. The direction of twist refers to the direction of inclination of the coils of a wire or cord when it is held vertically. If the inclination of the spirals conforms to the inclination of the letter "S", then the twist is called "S" or "left hand". If the inclination of the spirals conforms to the inclination of the letter "Z", then the twist is called "Z" or "right hand". An "S" or "left hand" twist direction is understood to be the opposite direction of a "Z" or "right hand" twist. "Twist of yarn" is understood to mean the twist provided to a yarn before the yarn is incorporated into a string, and "cord twist" is understood to mean the twist provided to two or more yarns when they are twisted together with one another. the other to form a cord. "Dtex" is understood to mean the weight in 10 000 meter grams of a yarn before the yarn has a proportionate twist to it.

A helically wound strip, forming a wrapping layer 18, may be radially overlapped outside the outermost belt web 17 and may extend transversely over the axially wider portion of the webbing 16, 17. The helically wound strip may be fabricated from strands. organic hybrids reinforced with elastomeric material such as nylon. Nylon is understood to be an aliphatic polyamide 6, 4.6 or 6.6.

Conventional wrap reinforcements have used a "one by one" nylon construction such as 940/1 Dtex 4.6S TPI ("Twists per inch") or 1400/1 Dtex 4.6S TPI as a cost effective option. Indeed, a "one by one" construction with a low torque and corresponding high modulus can control tire growth, limit resting waves, and achieve good high speed performance.

However, such "one by one" constructions do not meet certain high speed requirements for high performance tires. Thus, conventional "by two" constructions such as 1400/2 Dtex 6/6 TPI, 1400/2 Dtex 8/8 TPI1 or 1400/2 10/10 TPI have been implemented for such high speed requirements.

It may be desirable to use a "one by one" construction for a wrapper that can effectively replace conventional "two by one" constructions, which are of larger production and usually exhibit smaller modulus. According to the present invention, a wrapper for a high performance tire may have nylon reinforcing cords with a unique construction of 2000-2200 / 1 Dtex with a 1-10 TPI twist (S or Z). In addition, according to the present invention, another wrapper for a high performance tire may have nylon reinforcing cords with a unique construction of 2400-2600 / 1 Dtex with a twist of 1-10 TPI (S or Z). In addition, according to the present invention, yet another wrapper for a high performance tire may have unique nylon reinforcing cords of 2700-2900 / 1 Dtex with a twist of 1-10 TPI (S or Ζ). The wrapper can still display 10-35 EPI ("ends per inch") of such strands. Such a wrapper can provide a cost effective detained construction while still achieving equal or better high speed performance compared to conventional 1400/2 Dtex constructions.

Furthermore, the simpler construction of the wrapper fabric according to the present invention may allow reduction of fabric production time and cost due to larger Dtex yarn being cheaper than smaller Dtex yarn. Also, the larger module of the 2000-2200 / 1 Dtex wrap construction in accordance with the present invention can provide better high speed performance and less flatspotting than conventional 1400/2 Dtex constructions.

The table below expresses a comparison of the tensile characteristics of a 2100/1 Dtex 4.6S TPI wrapper construction of the present invention and three other constructions. As the table illustrates, the 2100/1 Dtex 4.6S TPI construction of the present invention provides acceptable tensile characteristics compared to the conventional 1400/2 Dtex 6/6 TPI cord construction while being much less expensive to produce. . Still, while the 2800/1 Dtex 4.6S TPI1 construction and another construction according to the present invention have more desirable tensile characteristics, it is significantly more expensive than the 2100/1 Dtex 4.6S TPI construction. In addition, a 2500/1 Dtex 1-10 (S or Z) TPI construction according to the present invention desirably provides superior traction characteristics to the 2100/1 Dtex 4.6S TPI construction while being cheaper than the 2800/1 construction. 1 Dtex 4.6S TPI.

<table> table see original document page 8 </column> </row> <table>

In a tire, such as the example tire 10, the nylon reinforced helically wrapped wrap 18 according to the present invention may be superimposed externally on the outer belt web 17. The helically wrapped wrap structure 18 may overlap the lateral ends of the radially outer belt web 17 by a few millimeters and may provide stiffness in the circumferential direction as well as a uniform pressure distribution on the tread surface.

Although the wrapper structure 18 described above has one layer, it may also comprise a second layer located adjacent to and radially outside the first layer. The second layer may have its helical convolutions with the opposite hand to the first layer so that the nylon strands of each layer intersect at a very small angle. With such a construction, the two layers can be continuously rolled in succession without a break in the strip. The helical coiled convolutions of the helically wound strip, instead of being bound by any adjacent convolution, may also have an overlap relationship with the previous convolutions, the overlap of which may be constant or variable across the width of the belt reinforcement structure. 15 without departing from the spirit of the present invention.

Further, it is well known that helical convolutions of a pneumatic tire construction on a cylindrical drum are subjected to different elongations during the conformation and vulcanization step of the tire manufacturing process because the pneumatic expansion is greater in the center portion than in the tire portions. shoulders of the belt reinforcement structure. In order to minimize the resulting differences in strap pulls, the center belt strap can be wound with a very small take-up tension as compared to the take-up tension used when fabricating the de-pneumatic shoulder portion of the strap.

Alternatively, the surface of the cylindrical drum on which the strip is helically wound may be slightly convex in shape. This convex shape may conform as closely as possible to the sectional radial shape that the wrapper 18 may take on the finished tire so as to obtain a minimum stretch difference between the center and shoulder portions of the wrapper during shaping and curing.

An uncured radial tire expands by about three per centodurant during conformation in the tire mold. This conformation performs a pantograph of the straps of the webbing, and a pre-tensioning of the strands reinforcing the canvas or carcass lining as much as these strands cannot slide around detail cores. Nylon cords reinforcing the helically wound wrap of the example tire may also be pre-tensioned during the forming operation and by suitable choice of an uncured tire size and mold shape. It is understood that a curing temperature of 160 ° C to 200 ° C can only effect a slight contraction of the nylon strands, the effect of which comes in addition to the conformation.

The above results clearly demonstrate the excellent high speed performance of tires manufactured in accordance with the teachings of the present invention. While a particular form of the present invention has been illustrated and described, it will also be apparent to those skilled in the art that various modifications may be made. made to escape the spirit and scope of the invention. Similarly, the invention is not intended to be limited in any way except by the claims set forth.

Claims (5)

1. Pneumatic tire, CHARACTERIZED by a radial tarpaulin casing, a tread arranged radially out of the carcass and a reinforcing structure interposed between the tread portion and the carcass in relation to the carcass, the reinforcing structure crown including a belt assembly having at least one belt web with reinforcing cords extending parallel to each other and a wrap structure including a nylon reinforced layer extending transversely over the belt assembly and at an angle of - 5 degrees to +5 degrees to the common equatorial plane of the tire, the nylon reinforced layer including nylon cords having a construction of 2000-2200 / 1 Dtex, 1-10 TPI with an end density of 10-35 EPI. Pneumatic tire according to claim 1, characterized in that the wrapping structure has two layers with a second layer located adjacent to and radially outside a first layer. Pneumatic tire according to claim 1, characterized by the fact that the wrapping layer includes a strip having a width in the range of between 5 mm and 30 mm. 4. Pneumatic tire, CHARACTERIZED a radial tarpaulin casing, a tread arranged radially out of the carcass and a reinforced corona structure interposed between the tread portion and the carcass circumferential to the carcass, the corona reinforced structure including an assembly having at least one belt web with reinforcing cords extending parallel to each other and a wrap structure including a nylon reinforced layer extending transversely over the belt assembly and at an angle of between -5 degrees and + 5 degrees with an equatorial plane of the tire, the nylon reinforced layer including nylon strands having a construction of 2400-2600 / 1 Dtex, 1-10 TPI with an end density of 10-35 EPI. 5. Pneumatic tire, CHARACTERIZED by a radial tarpaulin casing, a radially disposed derailing band outside the casing and a corona reinforcement structure interposed between the tread portion and the carcass in a circumferential relationship to the carcase, the crown reinforcement structure including a belt assembly having at least one belt web with reinforcing cords extending parallel to each other and a wrap structure including a nylon reinforced layer extending transversely over the belt assembly and making an angle of between -5 degrees and + 5 degrees with an equatorial tire plane, the nylon reinforcement layer including denon cords having a construction of 2700-2900 / 1 Dtex, 1-10 TPI with an end density of 10-35 EPI .